Why can some marine creatures see things without eyes?

 Why can some marine creatures see things without eyes?

The unusual ability of the red sea snakes tail is attributed to the photoreceptor and pigment cells that cover its whole body. Pigment cells move throughout the day, helping them change color dramatically, from dark reddish brown during the day to striped Beige at night.

The sea snake tail extends five radiating arms from the central disk. It is related to starfish, sea cucumber, sea urchin and a group of marine invertebrates called echinoderms. These animals have nervous systems but no brains.

According to the report, the red sea snake tail lives in a bright and complex environment and is under high threat of being preyed on by coral reef fish. It hides during the day and comes out at night to eat debris.

Its photoreceptor cells are surrounded by pigment cells in the daytime, reducing the range of detected light, so that each photoreceptor cell is like a pixel of a computer image, when combined with other pixels, it will generate a complete image. When pigment cells contract at night, the visual system does not work.

If our conclusions about pigment cells are correct, then this is a perfect example of evolutionary innovation, said Lauren Sumner Rooney, a researcher at the Oxford University Museum of natural history who led the study (compiled by / Wang Haifang)

Source: Wang Fengzhi, NT2541, editor in charge of the information network